This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The overall objective of the project is to assess the risk of emergence of new HIV groups from simian immunodeficiency virus (SIV) - infected persons in Cameroon and the Republic of Congo. It is well established that HIV-1 emerged through cross-species transmission of SIV in chimpanzees (cpz) to humans who were exposed through hunting, preparation of bush meat or household pets. Our hypothesis is that SIVcpz human infections have a low intrinsic pathogenicity after direct cross-species transmission from the natural chimpanzee hosts to humans. These primary SIV infections do not spread from person to person at a level sufficient to sustain the emergence of new epidemic groups, comparable to HIV-1 groups M, O or HIV-2 groups A and B. The hypothesis predicts that SIVcpz will replicate to significant levels during acute human infections but will be controlled in the chronic stage. The project heads in Cameroon and the Congo will coordinate and oversee a team for screening the general human population in Southwest anglophone Cameroon and the Congo for SIV infections. The focus will be on blood bank specimens where the project will have access to HIV+ and HIV indeterminant samples. Blood will be used for antibody assays to detect SIVcpz and other strains of SIV. We will also employ PCR-based testing and genome sequencing to identify particular strains of SIV. Some testing will be done on sight in Cameroon, but the majority of laboratory work will be done on specimens sent to the USA. The Laboratories in Congo are better equipped for in country conducted assays. After identifying persons with SIV infections, we will characterize the epidemiology and natural history of SIV infections in humans. Contacts will be tested to determine if these simian retroviruses are capable of transmissible between humans. The outcome of these infections in humans will be also clinically addressed. SIV antibody positive persons will have repeated clinical follow-ups. Thus far, SIV-like infections in humans are believed to be transient infections, but this has not been extensively studied and is the goal of this project. To accomplish our aims, the teams in Cameroon and Congo will collect basic epidemiological information about the entire population sample and a brief history of their past exposure to SIV [unreadable]e.g. hunting and butchering monkeys and contact with household pets. The goal is to test approximately 16,000 to 20,000 blood samples over 4 years, of which we anticipate detecting approximately 40 SIV infected humans. For this group of 40, we will follow up with a detailed assessment of potential risk factors for transmission of their SIV infections to other humans [unreadable]including household exposure (e.g. sharing utensils, shaving gear, toothbrushes), sexual contacts, mother-to-child, ritual cutting/scarification, and histories of medical care [unreadable]especially invasive procedures associated with transmission of blood borne viruses [unreadable]e.g. injections, surgery, and blood transfusions.